First, we strongly recommended using the synovial α‐defensin ELISA test as a reliable diagnostic test for chronic PJI after excluding the IA diagnosis; while other synovial tests (except synovial IL‐6 and TNF‐α) could also be treated as surrogates if the α‐defensin ELISA test is unavailable in some areas. The gene discussed is IL6; the disease is juvenile polyposis syndrome.